Loans and Allowance for Loan Losses - Financing Receivable, Troubled Debt Restructuring (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Construction and land development
Troubled Debt Restructuring Loans Modified Term			$ 31
Troubled Debt Restructurings Total New Modifications			31
Commercial business
Troubled Debt Restructuring Loans Modified Combination	$ 22
Troubled Debt Restructurings Total New Modifications	22
Consumer other
Troubled Debt Restructuring Loans Modified Term	16	$ 136	535
Troubled Debt Restructuring Loans Modified Combination	1,951
Troubled Debt Restructurings Total New Modifications	1,967	136	535
Newly Restructured Modified Loans
Troubled Debt Restructuring Loans Interest Only			1,348
Troubled Debt Restructuring Loans Modified Term	16	136	566
Troubled Debt Restructuring Loans Modified Combination	3,562		106
Troubled Debt Restructurings Total New Modifications	3,578	$ 136	2,020
Commercial Real Estate
Troubled Debt Restructuring Loans Modified Combination	559
Troubled Debt Restructurings Total New Modifications	559
Commercial construction
Troubled Debt Restructuring Loans Modified Combination			106
Troubled Debt Restructurings Total New Modifications			106
One- to four-family residential
Troubled Debt Restructuring Loans Interest Only			1,348
Troubled Debt Restructuring Loans Modified Combination	1,030
Troubled Debt Restructurings Total New Modifications	$ 1,030		$ 1,348